c++ operation order...

Question

#include <iostream>
using namespace std;

int main() {
cout<<(1||0);
cout<<(1&&0);
cout<<((1||0)&&0);
cout<<(1||0&&0);
return 0;
}

I can't understand why the output of third one and last one is different...sad...

Answer 1

The logical and (&&) operator has higher precedence than the logical or (||) operator. So (1||0)&&0 is 0, because 1||0 = 1 and 1&&0 = 0. On the next line, the and gets evaluated first, so you get 1||(0&&0), so 1||0 = 1. You can see the operator precedence table here: http://en.cppreference.com/w/cpp/language/operator_precedence